Nowadays, components which are intended for use at high temperatures are generally provided with protective layers. These may be metallic corrosion-resistant layers (MCrAlX layers) or ceramic thermal barrier coatings, as well as layer systems comprising both metallic corrosion-resistant layers and ceramic thermal barrier coatings. Plasma-enhanced powder spraying processes are used as the coating process for these coatings, on account of their relatively favorable economics. Layers of this type are attached to the substrate by mechanical interlock and subsequent diffusion heat treatment. In operation, the layer may become detached on occasion in highly stressed regions or at unfavorable areas of the component, i.e. areas which are subject to particularly high mechanical stresses. The layer flaking off in operation leads to damage to the base material, with the result that the component life is significantly reduced.
U.S. Pat. No. 5,869,798 discloses a process in which elevations are produced on a surface by means of a welding process, the elevation consisting of a different material than the underlying substrate.
EP 1 275 748 A2 discloses anchoring means which are arranged on a surface of a substrate or of an interlayer or project through a plurality of layers.
DE 100 57 187 A1 discloses anchoring means which project into a metallic substrate in order to improve the bonding of a metallic material, such as ceramic, to the metallic substrate. The anchoring means do not extend as far as an outer surface.
EP 0 713 957 A1 discloses a process in which a recess in a layer is filled with material.
Further prior art is known from DE 30 38 416 A1and from Journal of Materials Science 24 (1989), pages 115–123, entitled “Enhanced metal-ceramic adhesion by sequential sputter deposition and pulsed laser melting of copper films on sapphire substrates” by A. J. Pedraza, M. J. Godbole.